ST L4983 PFC Controller Integrates 7A Totem-Pole Driver for Kilowatt Supplies

STMicroelectronics has released the L4983, a power-factor correction controller that integrates a totem-pole output stage rated at 7A sink current and 3A source current. The integration target is explicit: engineers can build continuous conduction mode (CCM) PFC circuits with very few external passive components. ST positions the part for power supplies ranging from several hundred watts to multiple kilowatts.

The device arrives as equipment makers face tightening efficiency and harmonics rules on several continents. It targets systems that must meet EN 61000-3-2 and similar specifications worldwide, including the Japanese JEIDA-MITI standard. Typical applications named by ST include industrial and medical power supplies, high-power luminaires, servers, PCs, and home electronics.

What does the controller integrate?

The core of the design is a proprietary multiplier emulator paired with distortion-optimization circuitry. Together they let the chip shape input current with minimal external support. The single integration that carries the story is the gate driver itself: a 7A sink, 3A source totem-pole output strong enough to switch power stages directly, without a separate driver IC.

The controller also supports three power-saving modes. These help equipment meet efficiency guidelines including Energy Star in the United States and the EU Ecodesign Directive. The three modes work as follows:

• Burst mode stops switching activity automatically during light or zero load conditions, and resumes quickly as load increases without requiring a soft restart.
• Pin-controlled idle mode suspends switching and turns off the internal error amplifier.
• Disable mode supports a soft-start when the controller is brought back into operation.

How does the L4983 protect the power stage?

Protection coverage is broad for an SO-8 device. Overvoltage protection stabilizes the output during transients. Cycle-by-cycle overcurrent protection uses an internal comparator. Inductor-saturation detection prevents abnormal currents and surges. Line feedforward stabilizes output power as the AC input fluctuates, a function that directly addresses wide-input-range designs.

The startup path is protected as well. The controller supports soft-start and protects against feedback loop failures by verifying voltage-feedback and current-sense signals at startup. This verification closes a common failure mode in PFC stages, where a broken feedback loop can drive the output to destructive levels before the control loop catches it.

Which variants and tools are available?

ST offers two versions of the part. The L4983A operates at a switching frequency of 65kHz, and the L4983B operates at 130kHz. Both come in the compact SO-8 surface-mount package. The frequency split gives designers a direct trade: the 130kHz B-version shrinks magnetics, while the 65kHz A-version reduces switching losses and EMI filtering burden in high-power designs.

For development, ST supplies the EVL4983-350W demonstration board. The board accelerates development of switched-mode power supplies built around the L4983 and gives engineers a working reference for a mid-range point in the part's several-hundred-watt to multi-kilowatt envelope.

The commercial logic behind the part is consolidation. By folding the driver, the multiplier emulator, distortion optimization, and a layered protection suite into an 8-pin package, ST reduces external bill-of-material count in a market where passive components dominate PFC cost and board area. That consolidation matters most at the kilowatt scale, where server and industrial power supplies face the strictest readings of EN 61000-3-2. With two frequency grades and a ready evaluation board, ST has covered both the efficiency-first and size-first design paths, and the L4983 family should see adoption first in server and medical supplies where compliance deadlines drive redesign cycles.